芽孢杆菌对桉树幼苗的促生效果及其ACC脱氨酶活性的研究

【目的】筛选出能显著促进桉树幼苗生长的芽孢杆菌菌株,探究酶活性与桉树幼苗生长的相关性,初步揭示芽孢杆菌对桉树幼苗的促生机制。【方法】以分离自广东广州、阳江桉树林地土壤的32个芽孢杆菌菌株为研究对象,测定桉树幼苗接种盆栽试验以及菌株ACC脱氨酶活性与幼苗N、P养分。【结果】接种菌株2306、2403、2301能够显著促进桉树幼苗高生长和生物量积累,尤以菌株2306的促生效果最佳,其苗高、生物量分别比对照增加53.1%和190.2%。【结论】芽孢杆菌的ACC脱氨酶活性与桉树幼苗高生长相关极显著,与生物量相关显著;而且上述3个菌株均能提高桉树幼苗的N、P含量。研究结果将进一步丰富桉树促生菌资源,促进桉树微生物肥料的开发。

Growth-promoting effect of Bacillus strains on Eucalyptus seedling and their ACC deaminase activity

Objective] aiming to screen out Bacillus strains which promoted growth of Eucalyptus seedlings, estimate relationship between ACC deaminase activity and seedling growth performances, and reveal preliminarily mechanism of growth promotion by Bacillus strains. Methods] Pot experiment was conducted for Eucalyptus seedlings inoculated by 32 strains of Bacillus which were isolated from the soil under Eucalytus plantation in Yangjiang and Guangzhou City, Guangdong Province, and ACC deaminase activity of the strains as well as nitrogen and phosphorus contents of the seedlings were measured. Results] The results showed that inoculations of strains 2306, 2301 and 2403 could increase significantly height and biomass growth of Eucalyptus seedlings, and strain 2306 was the best, relevant seedling height and biomass were 53.1% and 190.2% higher than control. Conclusion] ACC deaminase activity of Bacillus strains was remarkably correlated with seedling height and biomass, and these three strains could also increase nitrogen and phosphorus contents of Eucalyptus seedlings. The findings will increase growth-promoting microorganism germplasm resources of Eucalyptus plantation and facilitate development of microbiological fertilizers for Eucalyptus.